Implantable prosthetic valve

ABSTRACT

A prosthetic valve for implantation within a fluid conducting lumen within a body includes an elongate generally cylindrical radially collapsible valve body scaffold defining a fluid passageway therethrough for retentive positioning within the lumen. A radially collapsible leaf valve member is supported by the scaffold includes a number of valve leafs deflectable between a closed position restricting fluid flow through the passageway and an open position permitting fluid flow through the passageway. The leaf valve member includes an interior leaf valve frame defining a valve leaf aperture which is sealed by a fluid impermeable non-thrombogenic lining to prevent fluid flow therethrough.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a division of U.S. application Ser. No.09/425,142, filed Oct. 21, 1999, now allowed.

FIELD OF THE INVENTION

[0002] The present invention relates to the field of implantableprostheses. More specifically, the present invention relates toimplantable prosthetic cardiac, aortic, and venous valves.

BACKGROUND OF THE INVENTION

[0003] In human pathology, the proper functioning of both cardiac andvenous valves is of paramount importance. Disorders of cardiac valvescause significant morbidity and mortality. These disorders affectpersons of all ages and can result from congenital or degenerativeconditions, as well as from the sequelae of infections. Stenosis andinsufficiency of the aortic or mitral valves have a greater incidencethan stenosis and insufficiency of the tricuspid and pulmonary valves.Venous insufficiency is believed to contribute to various maladies,including edema, varicose veins, aching leg pain while standing,lipodermatosclerosis, and ulcerations. Venous insufficiency isessentially caused by venous hypertension and chronic venous stasis dueto valvular incompetence both of an idiopathic nature and of a secondarynature following past illnesses of the venous systems.

[0004] A prosthetic cardiac or venous valve may regulate the directionof the pulsating blood flow so as to limit the occurrence of bloodstasis in the region about the valve. By maintaining the direction ofblood flow therethrough, a prosthetic cardia, aortic, or venous valvemay alleviate the maladies resulting from valve disorders or venousinsufficiency. A prosthetic valve should therefore permit blood flow inthe proper predetermined direction to limit or prevent backflow of theblood in a reverse direction.

[0005] The art has seen several attempts for providing a prostheticvalve to alleviate the consequences of cardiac valve disorders and ofvenous insufficiency. These attempts generally fall into two categories,biologic valves and mechanical valves. Biologic valves are comprised ofa stent supporting a number of circumferential leaflets made of aflexible material. If the material is biologic in nature, it may beeither a xenograft, that is, harvested from a non-human cadaver, or anallograft, that is, harvested from a human cadaver. For example, it isknown in the art to apply a pericardium biological tissue layercovering, for providing the valve leaflets, to a stent which providesstructural annular integrity to the prosthesis. Non-biologic materialsuch as polyurethane has also been used. The second category ofprosthetic valves, mechanical valves, usually comprise a rigid annulussupporting up to three rigid leaflets. The annulus and leaflets arefrequently formed in pyrolitic carbon, a particularly hard and wearresistant form of carbon. The annulus is captured within a sewing ringso that the valve may be attached to tissue at the location of thereplaced valve. Unfortunately, surgically positioning these implantstypically requires suturing or sewing the device into the blood vessel,increasing the risk of thrombosis due to the resulting suturing oranastomoses of the body vessel.

[0006] These attempts typically provide a valve structure having arelatively rigid tubular body structure which supports a flexible valveleaf structure. That is, any structural rigidity imparted to the tubularbody structure is separated from the valve leaf structure. For example,U.S. Pat. No. 4,759,759 discloses a prosthetic valve having a solidstent member having a diametrically-opposed upstanding posts and asubstantially cylindrical flexible cover. The two portions of the coverextending between the upstanding stent posts may be collapsed againsteach other in sealing registry over a fluid passageway defined by thestent. The stent, being a solid member, limits the radial collapsingthereof for endoscopic delivery within a body lumen. The cover, beingunsupported by the stent within the fluid passageway of the valve, mustitself provide sufficient strength and resiliency to optimally regulatefluid flow. Alternatively, U.S. Pat. No. 5,855,691 discloses aprosthetic valve having a radially expandable covered stent whichdefines an elongate fluid passageway therethrough. A flexible valve isdisposed within the fluid passageway to regulate fluid flowtherethrough. The valve is formed of a flexible and compressiblematerial formed into a disc with at least three radial incisions to formdeflectable leaflets. While the stent circumferentially supports thevalve body, the leaflets are not supported by any other structure withinthe fluid passageway. There is therefore a need in the art for a unitaryprosthetic valve construction which provides structural reinforcement toboth the tubular body portion of the valve and to the valve leafssupported thereon.

SUMMARY OF THE INVENTION

[0007] The present invention is directed to providing a fully prostheticvalve having valve leafs formed from a covered valve leaf frame andwhich may be implanted using a minimally-invasive, endoscopic technique.

[0008] The present invention provides a prosthetic valve forimplantation within a body lumen. The prosthetic valve of the presentinvention provides a device for regulating and maintaining the directionof a pulsating fluid flow through the body lumen. The valve includes aradially-collapsible scaffold portion and a radially-collapsible leafvalve portion. The scaffold portion includes a tubular open bodyscaffold defining a fluid passageway therethrough. The leaf valveportion is deflectable between a closed configuration in which fluidflow through the valve passageway is restricted and an openconfiguration in which fluid flow through the valve passageway ispermitted.

[0009] Each of the valve leafs desirably includes a valve leaf framehaving an open construction so as to facilitate radially-collapsing or-expanding the leaf valve portion of the valve. Each valve leaf framedefines a valve leaf aperture with the scaffold. The present inventionseals each valve leaf aperture to prevent fluid flow therethrough. Thematerial used to seal each valve leaf aperture is sufficiently thin andpliable so as to permit radially-collapsing the leaf valve portion fordelivery by catheter to a location within a body lumen. Afluid-impermeable biocompatible non-thrombogenic valve leaf cover may bepositioned on each valve leaf frame so as to seal the valve leafaperture. The valve leaf cover may be formed from a surgically-usefultextile such as Dacron, polyethlylene (PE), polyethylene terephthalate(PET), silk, Rayon, or the like. The valve leaf cover may also be formedof a surgically-useful polymeric material such as urethane,polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene(ePTFE). The valve leaf cover may also coated with a cellulargrowth-inhibiting drug such as Heparin or Taxol or another suchcomposition.

[0010] Similarly, each of the valve leaf apertures may be covered withcultured tissue cells derived from a either a donor or the host patientwhich are attached to the valve leaf frames. The cultured tissue cellsmay be initially positioned to extend either partially or fully intoeach valve leaf aperture. In order to provide additional support to theattached cultured tissue cells, a microfilter-type support mesh spanningthe valve leaf aperture may also be provided. The present inventionfurther contemplates that the supporting scaffold and valve leaf framesmay be formed of either a bioabsorbable material or a non-bioabsorbablematerial. It is contemplated that the scaffold and valve leaf frameswhich are formed from a bioabsorbable material will eventually bedisplaced by the tissue cells as the tissue cells mature. Eventually thecells alone will provide the fully functioning valve. Alternatively,when the scaffold and valve leaf frames are formed from anon-bioabsorbable material, the cultured cells provide a means forreducing any undesirable biological response by the host.

[0011] The leaf valve member is normally spring biased towards theclosed configuration. The present invention also contemplates biasingthe leaf valve member towards the open configuration to simulate knownanatomical mechanics of a valve in which the leaf valve portion wouldclose upon experiencing sufficient back flow pressure from the directiondownstream from the valve.

[0012] The leaf valve portion desirably includes a number of valve leafswhich are deflected between the closed and open configurations when thefluid pressure differential thereacross exceeds a predeterminedthreshold. That is, the fluid pressure differential acts to open thevalve when the fluid pressure upstream of the valve leaf portion isgreater than the fluid pressure downstream of the valve leaf portion.

[0013] Each of the valve leafs is deflectably supported by the scaffoldat a flexible hinge. The present invention contemplates that the openand closed configurations of the valve may be defined either downstreamor upstream of the flexible hinges. It is desired that the scaffoldportion of the valve will eventually provide fluid-tight engagement withthe body lumen although it is contemplated that some leaking or fluidflow between the scaffold portion and the body lumen is stillacceptable. Just as it is preferred, but not required, that the valveleafs prevent fluid flow in the closed configuration, it is recognizedthat substantial restriction of fluid flow past the scaffold-lumeninterface may still provide a prosthetic valve exhibiting acceptableperformance characteristics.

[0014] The present invention shows and describes both a bicuspid valveand a six-leaf valve, although designs employing a different number ofvalve leafs are clearly within the scope of the present invention. Thebicuspid valve includes a pair of leaf frames which deflect about ahinge positioned downstream of the closable valve opening. The six-leafvariant includes valve leafs which deflect about hinges positionedupstream of the closable valve opening.

[0015] The abutting engagement between adjacent valve leafs, whiledesirably providing a fluid-tight seal, is contemplated to significantlyrestrict backflow past the valve leafs. The abutting engagement betweenadjacent valve leafs may therefore provide less than complete fluidintegrity while still achieving the desired performance parameters.

[0016] The scaffold of the valve includes a first end defining a firstopening, a second end defining a second opening, a substantiallycylindrical interior face, a substantially cylindrical exterior face,and at least one radially-extending scaffold opening communicatingbetween interior and exterior faces. The interior face generally definesthe fluid passageway. The scaffold and leaf valve member are formed tobe expandable from a first diameter permitting delivery through the bodylumen to a second radially-expanded diameter for retentively engagingthe body lumen at a desired location. The scaffold may be formed havinga shape memory favoring radial self-expansion or may be formed so as topermit radial expansion by a delivery balloon which is deflated andwithdrawn after scaffold expansion against the body lumen. The scaffoldmay further provide at least one radially outwardly projecting hookmember for retentively engaging the fluid conduit when expandedthereagainst.

[0017] The present invention also contemplates forming both the scaffoldand the valve leaf frames as a unitary support trellis. The unitarytrellis may be formed by a single undulating wire bent to form both theradially expandable scaffold portion and the radially expandable valveleaf frames. While various configurations for the unitary supporttrellis of the present invention are contemplated, one preferredconfiguration bends a wire along a longitudinally extending andretracting undulating path so as to alternately define a collapsible andexpandable leaf frame aperture and then a collapsible and expandablescaffold aperture. The wire may be laid along a flat surface so as toform a planar trellis preform. The trellis preform may then be wrappedabout an elongate cylindrical mandrel. The valve leaf frames may bedeflected about their respective hinges to establish a shape memory ineither the open or closed configuration either prior to or afterwrapping the trellis preform about the mandrel.

[0018] The trellis is desirably formed from a biocompatible metal orpolymeric material. The trellis may additionally be formed from ashape-memory material to more reliably provide the required geometry tofunction effectively within the valve once radially expanded at a sitewithin a lumen. The trellis may be formed from an alloy of nickel andtitanium in specific proportions known in the art as nitinol.Alternatively, the trellis may be formed from a polymeric material whichallows the trellis to be radially collapsed for delivery to a site in alumen but then radially expands to return to an undeflected shape so asto function effectively within the valve.

[0019] The present invention also contemplates attaching an elongategenerally cylindrical first biocompatible non-thrombogenic liner to thetrellis. The first liner may be positioned on either the interior orexterior face of the scaffold. The first liner may also provide thesealing cover for the valve leaf frame apertures. The first liner may betrimmed to span between adjacent valve leafs in the open configurationso as to provide a larger surface area for the body fluid to act uponwhen urging the valve leafs between the open and closed configuration.The first liner may also be trimmed to provide at least one flapextending in the downstream direction beyond each valve leaf. Each flapmay then be folded over the adjacent valve leaf frame and laminatedthrough a valve leaf aperture to the liner.

[0020] Furthermore, an elongate generally cylindrical secondbiocompatible non-thrombogenic liner may be positioned on the scaffoldopposite the first liner. The second liner may desirably extend onlyalong a portion of the scaffold or fully along scaffold. The first andsecond liners may be joined so as to fully encase either just thescaffold or the entire trellis. It is contemplated that the first andsecond liners may be laminated together through one or more openingsdefined by the trellis. Additionally, the second liner may be formed byfolding the first liner over the first end of the scaffold so as toextend at least partially along the opposite face of the scaffold as thefirst lining.

[0021] Each liner positioned on the trellis may inhibit thrombusformation and facilitate tissue ingrowth therethrough for assimilatingthe valve of the present invention into the body lumen. Towards thislatter goal, one or both of the liners may be formed from a poroustextile or polymeric material. It is further contemplated that eitherliner may be formed from an xenograft of cellular tissue from a donorsuch as bovine cardial tissue, or homograft of cellular tissue formedfrom the host patient.

[0022] It is also contemplated by the present invention that theprosthetic valve may also be attached to the interior surface of asecond radially collapsible prosthetic fluid conduit. The second fluidconduit may be selected from many known stent and covered stent designsknown in the art. The second fluid conduit further maintains the patencyof the lumen to either side of the valve and may also include abiocompatible fluid impermeable non-thrombogenic lining on either orboth of its own inner or outer surfaces. The materials used to form thesecond fluid conduit may also be selected to be either bioabsorbable ornon-bioabsorbable as may be desired.

[0023] The present invention is also directed to methods of making theprosthetic valve of the present invention.

[0024] While the present invention has been described generally, thepresent invention will be more readily appreciated in a reading of the“Detailed Description of the Invention” with reference to the followingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 shows side elevational view of a prosthetic venous valve ofthe present invention in a closed, flow restricting configuration.

[0026]FIG. 2 shows a top elevational view of the prosthetic venous valveof FIG. 1 in the closed configuration.

[0027]FIG. 3 shows a side elevational view of the prosthetic venousvalve of FIG. 1 in an open, flow conducting configuration.

[0028]FIG. 4 shows a top elevational view of the prosthetic venous valveof FIG. 1 in the open configuration.

[0029]FIG. 5 shows the unitary support trellis of the prosthetic venousvalve of FIG. 1.

[0030]FIG. 6 shows a front elevational view of the unitary supporttrellis of the present invention in a flat trellis preformconfiguration.

[0031]FIG. 7 is a side elevational view of the unitary supportscaffolding and valve leaflet frames upon being stressed to provide fora self-closing valve.

[0032]FIG. 8 depicts one step in a method of constructing the prostheticvalve of the present invention by wrapping the unitary supportscaffolding and valve leaflet frames about a non-thrombogenic liningpositioned about a mandrel.

[0033]FIG. 9 shows an isometric view of a unitary support trellis for aprosthetic valve of the present invention.

[0034]FIG. 10 shows a perspective view of a prosthetic valve of thepresent invention in an open configuration and in which the scaffoldportion of the valve is substantially uncovered.

[0035]FIG. 11 shows a side elevational view of the prosthetic valve ofFIG. 10.

[0036]FIG. 12 shows a side elevational view of the prosthetic valve ofFIG. 10 in an open configuration.

[0037] FIGS. 13A-D depicts a further embodiment of the present inventionin which adjacent leaf frames are joined at a location therealong toreduce the size of the valve flow opening.

[0038]FIG. 14 shows an embodiment a prosthetic valve of the presentinvention in which a unitary support trellis is positioned over a liner.

[0039]FIG. 15 shows an alternate embodiment of a prosthetic valve ofFIG. 14 in which a second liner is positioned on the trellis to extendacross the proximal end of the scaffold portion.

[0040]FIG. 16 is a side elevational view of an alternate embodiment of aprosthetic valve of the present invention in an open, flow-conductingconfiguration in which a non-thrombogenic webbing spans between eachadjacent leaflet of the valve.

[0041]FIG. 17 shows an alternate embodiment of the present invention inwhich a secondary support scaffolding is formed to the downstream sideof the valve leaflets.

[0042]FIG. 18 shows a still further embodiment of the present inventionin which a number of deflectable valve leafs are attached within thefluid-conducting passageway to a radially-expandable prosthetic supportstructure.

[0043]FIG. 19 is a partial cut-away of the embodiment of FIG. 10depicting the valve leaflets in a closed, flow-restrictingconfiguration.

[0044]FIG. 20 is a partial cut-away of the embodiment of FIG. 11depicting the valve leafs in an open, flow-conducting configuration.

[0045]FIG. 21 depicts an alternate embodiment of a covered valve leaf ofthe present invention to be attached to a radially expandable outerconduit.

[0046]FIGS. 22 and 23 depict a prosthetic bicuspid valve of the priorart in the open and closed configurations, respectively.

[0047] FIGS. 24A-B are respective side and top elevational views of aprosthetic bicuspid valve of the present invention in the closedconfiguration.

[0048]FIG. 25A-B are respective side and top elevational views of aprosthetic bicuspid valve of the present invention in the openconfiguration.

[0049]FIG. 26A-B depict a unitary scaffold for the prosthetic bicuspidvalve of FIG. 24 in the closed configuration.

[0050]FIG. 26C depicts the scaffold for the prosthetic bicuspid valve ofFIG. 24 in the open configuration.

[0051] FIGS. 27A-B are respective side and top elevational views ofanother embodiment of the prosthetic bicuspid valve of FIG. 24, having alarger valve leaf and shallower valve cusp, in the closed configuration.

[0052] FIGS. 28A-B are respective side and top elevational views of theprosthetic bicuspid valve of FIG. 27A in the open configuration.

[0053] FIGS. 29A-B are side elevational views of the scaffold of theprosthetic bicuspid valve of FIG. 27A and FIG. 28A, respectively.

DETAILED DESCRIPTION OF THE INVENTION

[0054] The present invention relates generally to method and apparatusfor providing a fluid flow check valve for a body lumen. A preferredembodiment of the present invention is particularly suitable for formingan endoluminal prosthetic valve for vascular applications. Theprosthetic valve of the present invention regulates and maintains thedirection of a pulsating fluid flow through a body lumen. The prostheticvalve of the present invention is configured to open and close inresponse to the fluid pressure differential across the valve. The valveincludes a radially-collapsible scaffold portion and aradially-collapsible leaf valve portion which allows the valve to bedelivered via catheter through the body lumen in which it will beemplaced. The scaffold portion includes a tubular open body scaffolddefining a fluid passageway therethrough. The leaf valve portion isdeflectable between a closed configuration in which fluid flow throughthe valve passageway is restricted and an open configuration in whichfluid flow through the valve passageway is permitted.

[0055] The preferred embodiment of the prosthetic valve of the presentinvention is designed to be biased towards a closed, flow-restrictingconfiguration. The valve opens when sufficient fluid pressure is appliedto the leaflets from the upstream direction. Desirably the valve willopen when the pressure differential across the leaflets reaches about1-20 mm Hg. When the pressure differential is too low, the valve closesto prevent back flow. The valve desirably withstands up to about 100 mmHg of back flow pressure. When the pressure differential from bloodflowing the desired direction is removed, the valve returns to theclosed configuration.

[0056] As will be described in further detail hereinbelow for thesix-leaf variant of the present invention, the leaf valve portion isconnected to the scaffold portion so that the valve leafs aredeflectable about an annularly extending hinge line. The location of thehinge line along the length of the leaf valve portion influences thefluid pressure required to open and close the valve. In the closedconfiguration, the valve leaf portion substantially restricts fluid flowthrough the valve by providing a biocompatible impermeablenon-thrombogenic covering extending from the hinge line in registry withthe passageway.

[0057] Referring now to the drawings, FIGS. 1-5 depict a prostheticvalve 10 of the present invention. Valve 10 provides aradially-collapsible trellis 24 having an open construction. Trellis 24includes an elongate tubular body scaffold 30 supporting a number ofdeflectable valve leaf frames 52 deflectable about a hinge line 22. Eachvalve leaf frame 52 defines a leaf frame aperture 62 which is sealed bya valve cover 80 positioned on trellis 24. The remainder of trellis 24may also be covered with one or more liners 82 and 88, or may be leftuncovered altogether. The covered leaf frames 52 form the deflectablevalve leafs 40 which may be moved out of abutting engagement with eachother so as to permit fluid flow through valve 10 in response to thefluid pressure upstream thereof.

[0058] Valve 10 is provided for implantation within the fluid passagewayof a body lumen, such as for replacement of a cardial, arterial, orvenous valve, to regulate the flow of a bodily fluid therethrough in asingle direction. Valve 10 is constructed from biocompatible materialsso as to minimize any adverse body reaction to the implantation of valve10. Valve 10 includes an elongate tubular body portion 12 and a leafvalve portion 14. Valve 10 includes an upstream end 16, a downstream end18, and an elongate fluid passageway 20 extending therebetween along avalve axis l_(v). Leaf valve portion 14 is connected to body portion 12to extend in overlying registry with passageway 20. Leaf valve portion14 includes one or more valve leafs 40 which are deflectable withrespect to body portion 12 about a hinge line 22 between a closedconfiguration, shown in FIGS. 1 and 2, restricting fluid flow throughpassageway 20, and an open configuration, shown in FIGS. 3 and 4,permitting fluid flow through passageway 20. As shown in FIGS. 13A-D,hinge line 22 may be alternatively formed along the length of valveportion 14 by joining adjacent valve leafs 40 at a midway location 22′.Locating hinge line 22 further downstream from body portion 12 increasesthe required higher fluid pressure differential to deflect the valveleafs to the open configuration.

[0059] Leaf valve portion 14 may provide any number of valve leafs 40.While six valve leafs are provided and discussed by reference to FIGS.1-4, a bicuspid valve configuration is also contemplated and will befurther discussed hereinbelow. Still referring to FIGS. 1-4, each of thevalve leafs 40 are similarly-sized and -shaped and include opposed firstand second major surfaces 42 and 44, respectively. Each first majorsurface 42 of a valve leaf 40 is oriented in facing opposition towardsupstream end 16 of valve 10. Each of the valve leafs 40 provide asawtooth perimetrical edge formed by a first and second leaf edge 46 and48, respectively, which are positionable in abutting engagement with aleaf edge of an adjacent valve leaf 40 to define the closedconfiguration of valve 10. Similarly, as best shown in FIG. 4, the leafedges 46 and 48 define a valve leaf opening 50 when in the openconfiguration. Valve leaf opening 50 is in fluid communication withpassageway 20.

[0060] All of the valve leafs 40 are formed having a spring bias towardseither the open or the closed configuration. When all of the valve leafs40 are spring biased towards the closed configuration, the openconfiguration may be attained when the fluid pressure acting on thefirst major surfaces 42 of the valve leafs 40 overcomes both the fluidpressure acting on the second major surfaces 44 of the valve leafs 40 ofvalve 10 and any spring bias closing force imparted to the valve leafs40 acting to close the valve leafs. Should the fluid pressure from thedownstream end 28 of valve 10 become too great relative to the upstreamfluid pressure, the valve leafs 40 will also be urged towards the closedconfiguration. Each valve leaf 40 desirably curves inward such that thesecond major surface 44 has a concave shape to better collect backflowand urge the valve leafs 40 towards the closed configuration. Theprosthetic valve 10 of the present invention thereby provides a devicefor regulating and maintaining the direction of a pulsating fluid flowthrough the body lumen. While leaf valve portion 14 is normally springbiased towards the closed configuration, it is also contemplated,however, to bias leaf valve portion 14 towards the open configuration inorder to simulate known anatomical mechanics of certain valves. Thus,when biased towards the open configuration, leaf valve portion 14 wouldclose upon experiencing sufficient back flow pressure from thedownstream end 28 of valve 10.

[0061]FIG. 5 shows the unitary support trellis 24 employed by valve 10.Trellis 24 may be formed from a material exhibiting shape memorycharacteristics or from a material which is readily expandable by aballoon catheter. Trellis 24 is generally an elongate tube being coaxialwith valve axis l_(v). Trellis 24 has opposed upstream and downstreamends 26 and 28. Upstream end 26 of trellis 24 is further defined by aradially collapsible body scaffold 30. Downstream end 28 of trellis 24is further defined by a radially-collapsible leaf valve framework 32.

[0062] Trellis 24 may be formed from a wide variety of materials and ina wide variety of configurations. Radially-expandable endovascularstents known in the art provide useful basic designs for modificationinto a support trellis of the present invention and may be formed in awide variety of configurations. One example of a stent useful in thepresent invention is a slotted tubular stent which is designed toradially expand either by balloon catheter or by forming the stent froma temperature-sensitive memory alloy which changes shape at a designatedtemperature or temperature range. Other stent types, such astubular-shaped wire stents and self-expandable spring-biased stents arealso contemplated. Trellis 24 may therefore be formed from a variety ofmaterials including stainless steel, titanium, platinum, gold and otherbio-compatible metals. Shape memory plastics, polymers, andthermoplastic materials which are inert in the body may also be employedto form trellis 24. Shaped memory alloys having superelastic propertiesgenerally made from specific ratios of nickel and titanium, commonlyknown as nitinol, are among the preferred trellis materials.

[0063] With additional reference to FIG. 9, scaffold 30 is asubstantially cylindrical member having an interior face 34, an exteriorface 36 and defines at least one radially-extending scaffold opening 38communicating therebetween. Interior face 34 of scaffold 30 generallydefines passageway 20. It is contemplated by the present invention thatscaffold opening 38 need not be completely perimetrically bounded byscaffold 30. Scaffold 30 is formed to have a generally openconfiguration including a plurality of openings 38 communicating betweeninterior face 34 and exterior face 36. These openings 38 provide forlongitudinal flexibility of valve 10 as well as to permit valve 10 to beradially collapsed for delivery through, and radially expanded fordeployment in, a body lumen such as a blood vessel. Furthermore,scaffold 30 preferably maintains a substantially coaxial alignment withthe body lumen as leaf valve portion 14 deflects between the open andclosed configurations so as to better seal passageway 20 when valve 10is closed.

[0064] Leaf valve framework 32 includes a leaf frame 52 corresponding toeach valve leaf 40 of leaf valve portion 14. Each leaf frame 52 includesa first and second elongate component legs 54 an 56, respectively. Eachleaf frame 52 also has a length which is greater than the radius of theradially-expanded scaffold when implanted so as to minimize the risk ofa valve leaf 40 over-deflecting about hinge line 22 towards upstream end16 of valve 10. Each component leg 54 and 56 includes a proximal end 54a and 56 a, and an opposed distal end 54 b and 56 b, respectively. Eachleaf frame 52 is joined to scaffold 30 at a flexible hinge 60 defined bythe junction of the proximal ends 54 a and 56 a of each leg componentwith scaffold 30. For each valve leaf 40, hinge 60 includes space-aparthinge components 60 a, and 60 b. Additionally, the distal ends 54 b and56 b are contiguously formed. Each hinge component 60 a, 60 b may berespectively joined to the adjacent hinge component 60 b, 60 a of theadjacent leaf frame 52 in order to provide improved sealing of valve 10in the closed configuration. The joining of the hinge components 60 aand 60 b of adjacent valve leafs 40 further defines annular hinge line22.

[0065] Each leaf frame 52 defines a leaf frame aperture 62 with thedistal extent 31 of scaffold 30. Leaf frame aperture 62 communicatesbetween the first and second major surfaces 42 and 44 of valve leaf 40.The shape of leaf frame 52 is selected so as to assist and not inhibitthe radial contraction of valve 10 for delivery via catheter through abody lumen. Additionally, leaf frame 52 is formed having a curveimparted thereto so as to provide a concave shape to second majorsurface 44 of leaf 40. Each leaf frame 52 is imparted with a shapememory so as to extend over passageway 20 in either the open or closedconfiguration.

[0066] Trellis 24 is preferably formed by a single wire 70 contoured toform both scaffold 30 and leaf valve frame 32. As shown in FIG. 6, wire70 may trace a pattern on a flat surface so as to form a trellis preform74. Wire 70 may be longitudinally extended and retracted in anundulating pattern such that a valve leaf frame aperture 62 is formedand then a scaffold opening 38 is formed, although other paths arepossible. Each leaf frame aperture 62 and each scaffold opening 38 areperimetrically defined by a segment of wire 72 which allows trellis 24to be radially-collapsible to allow delivery of valve 10 through a bodylumen and then radially-expanded at a selected lumen site. Moreover,wire 70 may be welded, fused, crimped, sutured, or otherwise, joinedtogether at strategic locations such as at a scaffold joint 76 definedbetween circumferentially-adjacent scaffold openings 38. Additionally,wire 70 may be joined at or about hinge joints 76 where adjacent hingeportions 60a and 60b of adjacent valve leaf frames abut.

[0067] Referring to FIGS. 7 and 8, trellis preform 74 is bent into theshape of trellis 24 by wrapping preform 74 about an elongate cylindricalmandrel 78 and joining trellis preform ends 74 a and 74 b together, andthen deflecting the leaf frames 52 about hinge line 22 into overlyingregistry with passageway 20. Trellis 24 may be heat set in thisconfiguration by a method as is typically known for the material whichforms trellis 24.

[0068] The present invention seals each leaf frame aperture 62 toprevent fluid flow therethrough. The material used to seal each leafframe aperture 62 is sufficiently thin and pliable so as to permitradially-collapsing the leaf valve portion for delivery by catheter to alocation within a body lumen. Referring to FIGS. 10-12, afluid-impermeable biocompatible non-thrombogenic valve leaf cover 80 maybe positioned on trellis 24 so as to seal the leaf frame apertures 62.Preferably, valve leaf cover 80 seals the entire expanse of each leafframe aperture 62 prior to implantation although it is recognized thatthe lumen wall will also assist in sealing leaf frame aperture 62 in theregion about scaffold 30 adjacent hinge line 22. Therefore, valve leafcover 80 should minimally seal leaf frame aperture 62 between componentlegs 54 and 56 and hinge line 22 so that as scaffold 30 becomes embeddedin the lumen wall, valve 10 will fully seal at hinge line 22. Valve leafcover 80 may be formed from a thin layer of, by way of illustration andnot by limitation, PE, Pellethane, Urethane, bovine pericardial tissue,and the like. Alternatively, Valve leaf cover may be formed from asurgically-useful textile including, by way of illustration and not bylimitation, Dacron, Polyethylene terephthalate (PET), Polyethlylene(PE), silk, Rayon, or the like. Valve leaf cover 80 may also be formedof a surgically-useful polymeric material including, by way ofillustration and not by limitation, polytetrafluoroethylene (PTFE) orexpanded polytetrafluoroethylene (ePTFE). Valve leaf cover 80 isdesirably coated with a cellular growth-inhibiting drug such as Heparinor Taxol or the like.

[0069] Similarly, each valve leaf aperture 62 may be covered withcultured tissue cells derived from a either a donor or the host patient.The cultured tissue cells may be attached to each leaf frame 52 to thedistal extent 31 of scaffold 30 so as to seal each valve leaf aperture62. The cultured tissue cells may be initially positioned on a microfilter type mesh so as to extend either partially or fully into eachvalve leaf aperture 62. Scaffold 30 and leaf frames 52 may be formed ofeither a bioabsorbable material or a non-bioabsorbable material so thateach will eventually be displaced by the tissue cells as the tissuecells mature. Eventually, then, the cells alone will provide the fullyfunctioning valve. Alternatively, when scaffold 30 and leaf frames 52are formed from a non-bioabsorbable material, the cultured cells providea means for reducing any undesirable biological response by the host.

[0070] FIGS. 13A-D depict a still further embodiment of the presentinvention in which adjacent valve leaf frames 24 are joined at alocation along the length thereof so as to provide a smaller opening 50′in the open configuration. Adjacent component legs 54 and 56 may bejoined by welding or other techniques so as to form a hinge line 22′ ata location downstream from the distal extent 31 of scaffold 30. As thesize of opening 50′ affects the required actuation pressure differentialacting upon the valve leafs 40, it is contemplated that the preciselocation at which adjacent valve leaf frames 24 are joined may beselected in accordance with the fluid flow pressure parameters at thesite within the body in which the valve of the present invention isemplaced.

[0071] Referring again to FIGS. 1-4 and with additional reference toFIGS. 14-16, an elongate generally cylindrical first biocompatiblenon-thrombogenic liner 82 is attached to trellis 24. First liner 82 maybe positioned over either of interior face 34 or exterior face 36 ofscaffold 30. First liner 82 may also be provided in addition to, or inplace of, valve leaf cover 80 for sealing the leaf frame apertures 62.FIG. 15 depicts first liner 82 positioned on the interior 34 of scaffold30. Furthermore, first liner 82 may be trimmed to conform closely to thevalve leaf frames, as shown in FIG. 15. As shown by FIG. 16, first liner82 may include a valve webbing 84 trimmed to span between the edges ofadjacent valve leafs in the open configuration so as to provide a largersurface area for the body fluid to act upon when urging the valve leafs40 between the open and closed configuration. First liner 82 may also betrimmed to provide at least one flap 86 extending in the downstreamdirection beyond each valve leaf 40. Each flap 86 may then be foldedthrough the adjacent valve leaf aperture 62 and laminated to the firstliner spanning the other major surface.

[0072] Similarly, an elongate generally cylindrical second biocompatiblenon-thrombogenic liner 88 may be positioned on scaffold 30 oppositefirst liner 82. Second liner 88 may extend only along a portion ofscaffold 30, as shown in FIG. 15, or fully along trellis 24, as shown inFIG. 16. The first and second liners may be joined so as to fully encaseeither just scaffold 30 or all of trellis 24. Numerous techniques may beemployed to laminate or bond first liner 82 to second liner 88 throughthe scaffold openings 38 and the leaf frame apertures 62 of trellis 34including heat setting, adhesive welding, application of uniform forceand other bonding techniques. Additionally, second liner 88 may beformed by folding an extended length of first liner 82 over upstream end26 of scaffold 30 so as to extend at least partially along the oppositeface of scaffold 30 as first liner 82.

[0073] Each of liners 82 and 88 may be capable of inhibitting thrombusformation. Additionally, liners 82 and 88 may either prevent orfacilitate tissue ingrowth therethrough, as the particular applicationfor the valve may dictate. For example, liner 88 may be formed from aporous material to facilitate tissue ingrowth therethrough while liner80 is formed from a material or a treated material which inhibits tissueingrowth. Liners 80 and 88 may be formed from a surgically-usefultextile including, by way of illustration and not by limitation, Dacron,Polyethylene terephthalate (PET), Polyethlylene (PE), silk, Rayon, orthe like. Valve leaf cover 80 may also be formed of a surgically-usefulpolymeric material including, by way of illustration and not bylimitation, polytetrafluoroethylene (PTFE) or expandedpolytetrafluoroethylene (ePTFE). It is further contemplated that eitherliner 82 and 88 may be formed from an xenograft of cellular tissue froma donor such as bovine cardial tissue, or homograft of cellular tissueformed from the host patient.

[0074] The polymeric liners 82 and 88 and valve cover 80 of the presentinvention may be formed by a variety of methods. For example, extrusionprocesses such as ram extrusion; polymeric casting techniques such assolvent casting and film casting; molding techniques such as blowmolding, injection molding and rotational molding; and otherthermoforming techniques useful with polymeric materials may be employedand chosen to best serve the type of material used and specificcharacteristics of the liner or cover desired.

[0075] While either or both of the polymeric liners 80 and 88 may beprovided directly in tubular form, i.e as an extruded tube, either oneor both can also be formed from extruded sheets of material which can bewrapped around all or a portion of the support scaffold to form a coveror liner. Combinations of sheets and tubes are also contemplated and maybe applied to the support scaffold in a manner essentially as taught byU.S. patent application Ser. No. 09/035,501, which is hereinincorporated by reference. For example, in one embodiment a sheet may befirst formed and wrapped externally about the support scaffold andseamed along the longitudinal axis to form a cover. Such a sheet may bemade with a high degree of uniaxial orientation. The relative axis oforientation of the stent may vary depending on the material used to formthe liner or cover and the orientation and size of its pore structure.For example, in applicants' aforementioned copending U.S. applicationSer. No. 08/721,834, the extruded material used to form the liner orcover may be formed from unsintered ePTFE sheets which have beenexpanded longitudinally and aligned generally longitudinally along thelongitudinal stent axis, transverse to the longitudinal direction, or inan off-axis angle therebetween. In another example, a sheet or tube ofePTFE may be stretched and sintered several times to create a preformedePTFE having expansion memory, such as shown in PCT Publication No. WO96/00103 (U.S. application Ser. No. 0/95/07326), which is hereinincorporated by reference. This publication is based on U.S. priorityapplication Ser. No. 08/265,794, filed Jun. 27, 1994, which is alsoherein incorporated by reference. The preformed ePTFE allows for furtherexpansion once the stent is implanted and radially deployed. Otherembodiments of the present invention include the use of one or moretubes, providing a tube and a sheet formed into a tubular structure, orproviding a plurality of sheets formed into a tubular structure oneither surface of the stent.

[0076] Various bioeffecting agents may also be included in the liners bywell known methods. For example, anti-infective agents and/orantithrombogenic agents may be coated on the liner or disposed withinsome of the pores of the polymeric cover or conformal layer prior toimplantation. Additionally, such bioeffecting agents may also beemployed on the stent or in the anchoring material used thereon. Oneexample is shown in commonly assigned International Patent ApplicationNo. WO 95/29647, published on Nov. 9, 1995 and its U.S. priorityApplications Ser. No. 235,300, filed Apr. 29, 1994, and Ser. No.350,233, filed Dec. 1, 1994, which are incorporated herein by reference.

[0077] Referring again to FIG. 8, a method of forming a compositeendoluminal device of the present invention includes the steps ofproviding an inner liner 82 on an elongate cylindrical mandrel 78.Trellis 24 is positioned over liner 82. Trellis 24 may be positionedover liner 82 such that an extent 80a of liner 82 may be folded over theupstream end 26 of trellis 24 and positioned over an extent of theexterior face of scaffold 30, as shown in FIG. 15. Extent 80 a may beaffixed to liner 82 through the scaffold openings 38 or affixed toscaffold 30 itself. Extend 80 a may be positioned over the entire lengthof trellis 24, as shown in FIGS. 1 and 3. Alternatively, a second liner88 may be positioned on trellis 24 opposite first liner 82.

[0078] Still referring to FIG. 8, mandrel 78 may be formed to include ashaped end 78 a to serve as a die for shaping the closed configurationof the valve. Shaped end 78 a includes a contoured impression 78 c foreach valve leaf 40. Each valve leaf 40 may be deflected against itscontoured impression 78c to provide abutting engagement between theadjacent valve leafs. Trellis 24 may be shaped by shaped end 78 a eitherprior to or after covering with liners 80 or 88. It may be desirable toimpart the shape memory to trellis 24 prior attaching the liners.Additionally, while the leaf valve framework 32 is conformed to shapedend 78 a, the valve leafs 40 may be joined in accordance with theembodiment of FIGS. 13A-D, either before or after attaching one or bothof liners 80 and 88. It is further contemplated that each impression 78c may itself provide a contoured surface for imparting a curve to thedeflected valve leafs 40.

[0079] The present invention further contemplates positioning trellis 24about mandrel 78 without an underlying lining. Trellis 24 may thenreceive first lining over only the exterior face 36 of scaffold 30.Lining 80 may further be extended so as to cover the leaf frameapertures 62 of leaf valve frame 52, although it is contemplated using adifferent material to cover the leaf frame apertures 62. Lining 80 mayalso provide a valve webbing spanning between adjacent valve leafs 40.

[0080] It is additionally contemplated by the present invention to leavescaffold 30 substantially uncovered and to seal each leaf frame aperture62 to the extent required to provide an acceptable degree of flowrestriction in the closed configuration. While leaf frame apertures 62are desirably fully sealed prior to implantation, it is contemplatedthat only that portion of leaf frame aperture 62 which extends inregistry with fluid passageway 20 be sealed by one or more liners 80.The embedding of scaffold 30 into the body lumen would thereby providevalve 10 with an acceptable degree of fluid-integrity about the lumenwall. In such an embodiment, valve leaf cover 80 may be applied totrellis 24 to fully seal leaf frame aperture 62. The preferred methodincludes attaching a cover to both frame component legs 54 and 56 and tothe segment of distal scaffold extent 31 between the correspondinghinges.

[0081] Liners 82 and 88 may be formed of a polymeric material which maybe fused by various techniques such as heat sealing, solvent bonding,adhesive bonding, or use of coatings. It is also contemplated thatliners 80 and 88 may be formed of a textile material, or that each couldinclude a homograft or xenograft tissue retained by the intermediatemember to seal the openings in same. The formation, application, andorientation of liners 80 and 88 may be accomplished by the techniquesdescribed in commonly-assigned and copending U.S. patent applicationSer. No. 09/035,501, entitled “Conformal Laminate Stent Device”,which isincorporated by reference herein.

[0082]FIG. 17 shows an alternate embodiment of a trellis 148 for valve110 in which trellis 30 of valve 10 is mechanically joined to a secondradially collapsible scaffold 150. It is also contemplated that trellis30 of valve 10 may be continuously formed by the same wire 170 whichforms second scaffold 150. The present invention contemplates thatelongate portions 170 a of wire 170 may be employed between sections ofscaffolds to allow the prosthetic valve 10 to be emplaced withintortuously-extending sections of body lumen.

[0083] FIGS. 18-21 depict yet another embodiment of the presentinvention in which the valve leafs of an implantable prosthetic valve110 are attached to the interior lumenal surface 114 of a secondradially collapsible tubular fluid conduit 112. Second conduit 112 maybe selected from many known stent and covered stent designs known in theart. Second conduit 112 further maintains the patency of the body lumento either side of valve 10 and may also include a biocompatible fluidimpermeable non-thrombogenic lining 116 on either or both of its owninterior or exterior lumenal surfaces, 114 and 115, respectively. Thematerials used to form the second tubular fluid conduit may also beselected to be either bioabsorbable or non-bioabsorbable as previouslydescribed for liners 80 and 88.

[0084] Second conduit 112 includes a radially collapsible skeleton 120which may be formed from a shape memory alloy, an elastic metal, or apolymer. Second conduit 112 may also be formed of a bioabsorbablematerial. Outer surface 115 of second conduit 112 need not be covered asskeleton 120 will eventually embed into the lumen wall, but a lining 116may be preferable so as to limit flow-around until that time.

[0085] As shown in FIG. 19, a non-absorbable tether line 125 may haveends 125 a and 125 b affixed between second conduit 112 and each valveleaf 40 to prevent the leafs from inverting towards the upstream end 126of secondary conduit should the back flow pressure become sufficient toover-deflect the leafs past hinge line 22. Tether line 125 is desirablyaffixed at ends 125 a and 125 to non-bioabsorbable components of valve110.

[0086] With additional reference to FIG. 21, it is also contemplated bythe present invention to mechanically attach a number of covered leafframes 130 to the interior lumenal surface 114 of second conduit 112.Covered leaf frames 130 are similar in construction to valve leafs 40 ofvalve 10. Each covered leaf frame 130 includes a first and secondelongate component leg 132 and 134 welded or otherwise affixed toskeleton 120 at a hinge portion 135 comprising hinges 135 a and 135 bwhere the component legs attach. Covered leaf frame 130 defines a leafframe aperture 136 with skeleton 120 between the associated hinges 135 aand 135 b. A leaf cover 140 is desirably affixed over each leaf frameaperture 136 by spanning from each component leg 132 and 134 to skeleton120 between the hinges 135 a and 135 b so as to provide a fluidintegrity to the valve in the closed configuration. Alternatively, thecovered leaf frames could be attached to surface 114 along a leaf framestem 130 a.

[0087] Referring now to FIGS. 22 and 23, a prosthetic bicuspid valve 900of the prior art is depicted. Valve 900 is typical of a bubble valvedesign which provides first and second valve leafs, 902 and 904. Valve900 is formed having a solid interior stent frame which provides a pairof opposed raised posts which form raised hubs 906 a and 906 b. Theinterior stent is covered with a generally cylindrical cover 908 whichitself is formed of a flexible material. Valve flaps 902 and 904 areformed by the portion of cover 908 extending unsupported beyond theinterior stent structure. Valve flaps 902 and 904 must therefore rely onthe resiliency and shape memory of the material of the cover 908 for anybias towards the open or closed configurations. As shown in FIG. 23,cover 908 terminates at a flap edge 910 which, in the openconfiguration, defines a substantially circular opening through valve900. In the closed configuration, shown in FIG. 22, flap edge 910extends along a substantially catenary path between raised hubs 906 aand 906 b to seal valve 900.

[0088] FIGS. 24A-26 depict a prosthetic bicuspid valve 210 of thepresent invention. With like numbers indicating like components to otherembodiments of the present invention, bicuspid valve 210 is a bubblevalve including a support trellis 224 and a fluid impermeablenon-thrombogenic lining 280. Valve 210 is contemplated as a replacementaortic valve. Valve 210 is constructed from biocompatible materials soas to minimize any adverse body reaction to its implantation.

[0089] Valve 210 includes an elongate tubular body portion 212 and aleaf valve portion 214. Valve 210 includes an upstream end 216, adownstream end 218, and an elongate fluid passageway 220 extendingtherebetween along a valve axis l_(v). Leaf valve portion 214 extends inoverlying registry with passageway 220 and includes first and secondvalve leafs 240 and 241 which are deflectable between a closedconfiguration, shown in FIGS. 24A and 24B, restricting fluid flowthrough passageway 220, and an open configuration, shown in FIGS. 25Aand 25B, permitting fluid flow through passageway 220. Valve 210 alsoincludes a pair of diametrically-opposed valve hinge hubs 242 and 244about which valve leafs 240 and 241 deflect between the open and closedconfigurations. Hinge hubs 242 and 244 are located downstream of valveleafs 240 and 241 when valve 210 is in the closed configuration.

[0090] Valve leafs 240 and 241 are similarly-sized and -shaped andinclude opposed first and second major surfaces 240 a, 241 a and 240 b,241 b, respectively. Each first major surface 240 a, 241 a of a valveleaf 240 is oriented in facing opposition towards upstream end 216 ofvalve 210. Valve leafs 240 and 241 further include an arcuate leaf edge240 c and 241 c, respectively, which are positionable in abuttingengagement along a substantially catenary curve between hinge hubs 242and 244 to define the closed configuration of valve 210. Similarly, asbest shown in FIG. 4, the leaf edges 240 c and 241 c define aneye-shaped valve leaf opening 250 when in the open configuration. Valveleaf opening 250 is in fluid communication with passageway 220. Whereasthe valve leafs of the sawtooth valves of the present inventiondesirably had a longitudinal length greater than the radius of theimplanted scaffold, valve leafs of the biscupid valves of the presentinvention may be formed having a longitudinal length dimension 1 whichis smaller than the radius of the implanted scaffold portion.

[0091] Valve leafs 240 and 241 are desirably formed having a spring biasabout hinge hubs 242 and 244 towards the closed configuration. The openconfiguration may be attained when the fluid pressure acting on thefirst major surfaces 240 a and 241 a of the valve leafs 240 and 241overcomes both the fluid pressure acting on the second major surfaces240 b and 241 b of the valve leafs 240 of valve 210 and the spring biasimparted to the valve leafs 240 acting to close the valve leafs.Similarly, when the fluid pressure from the downstream end 218 of valve210 become too great relative to the upstream fluid pressure, the valveleafs 240 will be urged towards the closed configuration to thwart fluidflow through the valve back towards the upstream end 228.

[0092] FIGS. 26A-C show the support trellis 224 employed by valve 210.Trellis 224 may be formed from a material exhibiting shape memorycharacteristics or from a material which is readily expandable by aballoon catheter. Trellis 224 is generally an elongate tube beingcoaxial with valve axis l_(v). Trellis 224 has opposed upstream anddownstream ends 226 and 228. Upstream end 226 of trellis 224 is furtherdefined by a radially collapsible body scaffold 230. Downstream end 228of trellis 224 is further defined by a radially-collapsible leaf valveframework 232.

[0093] Trellis 224 may be formed from a wide variety of materials and ina variety of configurations. Radially-expandable endovascular stentsknown in the art provide useful basic designs for modification into asupport trellis of the present invention and may be formed in a widevariety of configurations. One example of a stent useful in the presentinvention is a slotted tubular stent which is designed to radiallyexpand either by balloon catheter or by forming the stent from atemperature-sensitive memory alloy which changes shape at a designatedtemperature or temperature range. Other stent types, such astubular-shaped wire stents and self-expandable spring-biased stents arealso contemplated. Trellis 224 may therefore be formed from a variety ofmaterials including stainless steel, titanium, platinum, gold and otherbio-compatible metals. Shape memory plastics and thermoplastic materialswhich are inert in the body may also be employed to form trellis 224.Shaped memory alloys having superelastic properties generally made fromspecific ratios of nickel and titanium, commonly known as nitinol, areamong the preferred trellis materials.

[0094] Scaffold 230 is a substantially cylindrical member having aninterior face 234, an exterior face 236 and defines at least oneradially-extending scaffold opening 238 communicating therebetween.Interior face 234 of scaffold 230 generally defines passageway 220. Itis contemplated by the present invention that scaffold opening 238 neednot be perimetrically bounded by scaffold 230. Scaffold 230 is formed tohave a generally open configuration including a plurality of openings238 communicating between interior face 234 and exterior face 236. Theseopenings 238 provide for longitudinal flexibility of valve 210 as wellas to permit valve 210 to be radially collapsed for delivery through,and radially expanded for deployment in, a body lumen such as a bloodvessel. Furthermore, scaffold 230 preferably maintains a substantiallycoaxial alignment with the body lumen as leaf valve portion 214 deflectsbetween the open and closed configurations so as to better sealpassageway 220 when valve 210 is closed.

[0095] Leaf valve framework 232 includes leaf frames 252 and 253corresponding to valve leafs 240 and 241. Leaf frames 252 and 253 defineleaf frame apertures 262 and 263 with the distal extent 231 of scaffold230. Leaf frame apertures 262 and 263 communicate between first andsecond major surfaces 240 a and 240 b of valve leaf 240, and first andsecond major surfaces 241 a and 241 b of valve leaf 241, respectively.Leaf frames 252 and 253 may be radially contracted towards valve axisl_(v) for delivery via catheter through a body lumen. Leaf frames 252and 253 are imparted with a shape memory so as to extend over passageway220 once implanted in a body lumen.

[0096] Leaf valve framework 232 further includes diametrically opposedhinge posts 245 and 247 extending from distal end 231 of scaffold 230towards hinge hubs 242 and 244, respectively. Hinge hubs 242 and 244extend transversely to valve axis l_(v). Arcuate frame portions 257 and259 of valve leafs 240 and 241 extend between hinge hubs 242 and 244along a substantially catenary path. As shown in FIGS. 25B and 26C,arcuate frame portions 257 and 259 deflect about hinge hubs 242 and 244and swings towards and away from each other as valve leafs 240 and 241are urged between the closed and open configurations.

[0097] Each leaf frame aperture 262 and each scaffold opening 238 areperimetrically defined by a segment of wire 270 which allows trellis 224to be radially-collapsible so as to allow delivery of valve 210 througha body lumen and then radially-expanded at a selected lumen site.Moreover, wire 270 may be welded, fused, crimped, sutured, or otherwise,joined together at strategic locations, such as at a scaffold joint 276defined between circumferentially-adjacent scaffold openings 238.

[0098] Trellis 224 is preferably formed by a single wire 270 contouredto form both scaffold 230 and leaf valve frame 232. Wire 270 may belongitudinally extended and retracted in an undulating pattern such thatone half of scaffold 230 is formed and a then a portion or all of valveleaf frame 232 prior to completing scaffold 230, although other pathsare possible. Alternatively still, trellis 224 may be formed inconstituent components which are then joined. Other methods for formingtrellis 224 as a unitary member will thus be apparent to those skilledin the art.

[0099] Liner 280 may be formed in accordance with the description forliner 80 hereinabove. Liner 280 may be applied to trellis 224 at eitherinterior face 234, exterior face 236, or at both faces. Liner 280 mayfurther be affixed only to trellis 224 or may include portions which areadhered to itself through the scaffold openings 238 and/or the leafframe apertures 262 and 263. It is contemplated that one of inner liner280 a and outer liner 280 b may be forced though trellis 224 to beaffixed to the other or both may be joined together within the scaffoldopenings 238 or the leaf frame apertures 262, 263.

[0100] The present invention further contemplates that the liner 280forming the major surfaces of valve leafs 240 and 241 are urgable into aconcave shape so as to better collect backflow and urge the valve leafstowards the open or closed configuration. The major surfaces of valveleafs 240 and 241 have complex shapes which are a function of thelongitudinal spacing of catenary frame portion from distal end 231 ofscaffold 230. Furthermore, the material forming the major surfaces neednot taughtly-extend across the leaf frame openings of valve leafs 240and 241. The present invention contemplates providing sufficient excessmaterial spanning leaf frame apertures 262 and 263 such thatoverwhelming fluid pressure acting on one major surface of a valve leafforces the covering through the valve leaf opening. When excess materialis applied across valve leaf apertures 262 and 263, then the first majorsurfaces of each valve leaf 240 and 241 may assume a concave shape so asto favor the opening the valve leafs and the second major surfaces mayassume a concave shape so as to favor closing the valve leafs.

[0101] FIGS. 27A-29B depict an alternate embodiment of a bicuspid valveof the present invention. Valve 310 is similar in most respects to valve210 described hereinabove but includes valve leafs 340 and 341 definedby leaf frame edges 357 and 359 having larger radius of curvaturebetween hinge hubs 342 and 344 than is shown in FIGS. 2-5. The largerradius of curvature along leaf frame edges 357 and 359 results in largermajor surfaces for the opposed valve leafs 340 and 341 and defines asmaller opening 350 in the open configuration, as shown in FIG. 28B. Itis contemplated that leaf frame edges 357 and 359 are deflectable to aposition coextensive with hinge hubs 342 and 344, as shown in FIG. 29B,or to a position downstream of hinge hubs 342 and 344, as shown in FIG.28B. It is also contemplated that the major surfaces 340 a and 341 a maycome into contact when valve leafs 340 and 341 are in the closedconfiguration.

[0102] While the present invention has been shown and described indetail above, it will be clear to the person skilled in the art thatchanges and modifications may be made wiyhout departing from the spiritand scope of the invention. That which is set forth in the g descriptionand accompanying drawings is offered by way of illustration only and notas a limitation. The actual scope of the invention is intended to bedefined by the following claims.

What is claimed is:
 1. A method of forming a prosthetic valve forimplantation within a body lumen, comprising providing a radiallycollapsible trellis having a tubular body scaffold portion defining anelongate fluid passageway for fluid flow therethrough and a valveleaflet frame portion having a number of valve leaf frames each defininga valve leaf frame aperture with the scaffold portion wherein said valveleaf frames are deflectable with respect to said scaffold portion so asto extend in overlying registry with the passageway between a firstposition and a second position, and sealing each said valve leafaperture with a biocompatible non-thrombogenic fluid impermeablematerial such that when the leaflet portion is in said first position,fluid flow through said passageway is substantially restricted.
 2. Themethod of forming a prosthetic valve of claim 1, further comprising thesteps of biasing each of said valve leaf frames towards the firstposition.
 3. The method of forming a prosthetic valve of claim 1,further comprising the step of biasing said valve leaflet portiontowards the second position whereby fluid flow through said passagewayis permitted.
 4. The method of forming a prosthetic valve of claim 1,further comprising the step of coating the material sealing each saidvalve leaf frame aperture with a growth inhibiting drug.
 5. The methodof forming a prosthetic valve of claim 1, further comprising the stepsof providing an elongate mandrel having a cylindrical outer surface;positioning a first biocompatible non-thrombogenic fluid impermeableliner over the outer surface of the mandrel; positioning said trellisover said first liner; and affixing said first liner to said trellis. 6.The method of forming a prosthetic valve of claim 1, further comprisingthe step of forming a radially collapsible trellis having a shapememory.
 7. The method of forming a prosthetic valve of claim 6, whereinthe step of forming a radially collapsible trellis further includeslaying a wire in an undulating manner in the shape of a preform of thetrellis.
 8. The method of forming a prosthetic valve of claim 7, whereinthe laying step further comprises the steps of alternately forming anaperture defined by a valve leaflet frame and said body scaffold andforming an opening defined by said scaffold portion.
 9. The method offorming a prosthetic valve of claim 1, further comprising the step ofdeflecting each said leaflet frame portion with respect to the bodyscaffold portion component to impart a shape memory to the preform inone of said first and second positions.
 10. The method of forming aprosthetic valve of claim 9, further comprising the step of imparting acurve to the leaflet frame.
 11. The method of forming a prosthetic valveof claim 9, wherein the imparting step further comprises the step ofheat setting a shape memory alloy at a temperature above its austeniticstart temperature in a desired shape.
 12. The method of forming aprosthetic valve of claim 5, further comprising the step of positioninga second biocompatible fluid impermeable non-thrombogenic liner over thescaffold.
 13. The method of forming a prosthetic valve of claim 12,further comprising the step of positioning said second fluid impermeableliner opposite said first liner.
 14. The method of forming a prostheticvalve of claim 12, further comprising the step of positioning saidsecond fluid impermeable liner to be substantially longitudinallycoextensive with said first liner along said scaffold portion.
 15. Themethod of forming of prosthetic valve of claim 14, wherein said step ofpositioning said second fluid impermeable liner opposite said firstliner and substantially coextensive with said first liner along saidscaffold portion further comprises positioning said second liner oversaid valve frame portion.
 16. The method of forming a prosthetic valveof claim 1, further comprising the step of providing anchoring means tothe prosthesis for engaging a lumen wall upon emplacement at a selectedsite of a body lumen.
 17. The method of forming a prosthetic valve ofclaim 1, further comprising the step of providing an elongate mandrelhaving a cylindrical outer surface; positioning said trellis over theouter surface of said mandrel; and positioning a first biocompatiblenon-thrombogenic fluid impermeable liner over the outer surface of saidtrellis.
 18. The method of forming a prosthetic valve of claim 1,further comprising the step of incorporating cultured tissue cells intosaid valve frame aperture.
 19. The method of forming a prosthetic valveof claim 18, further comprising the step of covering each said valveleaf frame with cultured tissues.
 20. The method of forming a prostheticvalve of claim 18, further comprising the step of forming each saidvalve leaf frame from a bioabsorbable material to be displaced by saidcultured tissue cells upon said cells maturing within the body lumen.21. The method of forming a prosthetic valve of claim 18, furthercomprising the step of forming said trellis from a bioabsorbablematerial.
 22. The method of forming a prosthetic valve of claim 18,further comprising the step of forming said trellis from a metallicmaterial.
 23. The method of forming a prosthetic valve of claim 22,further comprising the step of forming said trellis from a shape memorymaterial selected from the group consisting of an alloy of nickel andtin and a polymeric material.
 24. The prosthetic valve of claim 1,further including a second radially collapsible open tubular scaffoldhaving a cylindrical inner surface and an opposing cylindrical outersurface, said inner surface defining an elongate fluid conduit beingsubstantially coaxially-aligned with said passageway of said valve, saidsecond scaffold affixed to said body scaffold and extending at least oneof said upstream and downstream direction from said valve.
 25. Theprosthetic valve of claim 1, wherein said second scaffold furtherincludes a biocompatible fluid impermeable non-thrombogenic lining on atleast one of said inner surface and said outer surface.